Racismo, desgaste biológico e o risco de doenças cardiovasculares na coorte do ELSA-Brasil

Abstract

The objectives of this thesis were to develop and validate an estimate of biological age based on biomarkers from multiple systems in the Brazilian context (Article 1); investigate racial and social disparities in weathering (Article 2); and evaluate whether the association between racism and the incidence of major adverse cardiovascular events (MACE) is mediated by biological age (Article 3). We used data from visit 1 (2008-2010) of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), as well as mortality data after 10 years and MACE incidence data after 5 years of follow-up. Biological age was estimated at the first visit using the Klemera and Doubal method with clinical biomarkers. The difference between biological and chronological age (Δage) was used as a marker of biological wear. To validate this marker, we assessed its association with mortality using Cox proportional hazards models stratified by sex. The area under the curve (AUC) was used to evaluate the predictive power of Δage for mortality. Subsequently, we assessed the relationship between race/color, education, socio-occupational class, and intergenerational educational mobility with biological wear using linear regression models. The analyses were stratified by age (35-44 years; 45-54 years; and 55-73 years) to investigate whether wear is cumulative over time. Finally, we assessed the association between racism and the occurrence of MACE and verified if this association is mediated by biological wear using structural marginal models. The first article (N=12,109) showed that for each 1-year increment in Δage, mortality increased by 22% in men [HR(95%CI):1.22(1.18;1.27)] and 37% in women [HR(95%CI):1.37(1.24;1.51)] regardless of chronological age. The predictive power of the model that contained only chronological age was lower than those that included Δage in men [AUC chronological age =0.7324 versus AUC chronological age + Δage =0.7857; p=0.001] but not in women. The second article (N=11,064) showed that Browns [β(95%CI):0.52(0.42;0.63)] and Blacks [β(95%CI):0.85(0.72;0.97)] had greater wear than Whites. Individuals of low [β(95%CI):1.06(0.94;1.18)] and middle [β(95%CI):0.66(0.55;0.76)] socio-occupational class exhibited more wear than those of high class. Individuals with complete high school education [β(95%CI):0.74(0.64;0.84)], complete elementary education [β(95%CI):1.13(0.96;1.30)], and incomplete elementary education [β(95%CI):1.64(1.44;1.84)] had higher wear compared to those with a university degree. Individuals in the 1st [β(95%CI):0.82(0.66;0.98)], 2nd [β(95%CI):0.67(0.52;0.82)], and 3rd [β(95%CI):0.37(0.23;0.52)] income quintiles showed greater wear than those in the 5th (highest) quintile. Individuals with a downward [β=0.77; 95%CI=0.62-0.91] and low-stable intergenerational trajectory [β=1.01; 95%CI=0.90–1.12] exhibited more wear than those in the high-stable group. Finally, the results of the third article (N=10,983) showed that the MACE incidence was 63% higher among Blacks than Whites [HR(95%CI):1.63(1.01;2.65)]. This association was completely explained by weathering after weighting [HR(95%CI):1.05(0.61;1.79)]. There was no association among Browns. Our results suggest that biological age is an important explanatory mechanism for racial and social health inequities, reinforcing the theory that socio-environmental exposures are incorporated over time. Therefore, combating racism is crucial to improving the health of the Brazilian population.